The disclosed embodiments of the present invention relate to detecting letterbox margins of a frame, and more particularly, to a letterbox margin processing method for identifying letterbox margins within a target frame according to a frame packing type corresponding to a three-dimensional (3D) video input and related letterbox margin processing apparatus thereof.
Letterboxing is a practice of transferring a conventional two-dimensional (2D) movie originally filed in one aspect ratio (e.g., 21:9 or 4:3) to video frames each having another aspect ratio (e.g., 16:9 or 1.85:1) while preserving the movie's original aspect ratio. The resultant video frame therefore has letterbox margins (e.g., black bars) disposed above and below the video content with the preserved aspect ratio, or has letterbox margins (e.g., black bars) placed on a left side and a right side of the video content with the preserved aspect ratio. The letterboxed video frames of the filmed movie may be stored on an optical storage medium, such as a digital versatile disc (DVD) or a Blu-ray disc (BD). When the user loads the optical storage medium into an optical storage apparatus (e.g., an optical disc player), the letterboxed video frames may be displayed on a display apparatus to thereby allow the user to view the video content presented in the movie's original aspect ratio. However, the user may want to view the video content of the filmed movie on the display apparatus without the letterbox margins. Thus, conventional letterbox detection is performed to detect the letterbox margins in each letterboxed video frame, and then remove them from the letterboxed video frame to generate a margin-removed video frame. Next, the margin-removed video frame is scaled to a full screen/full resolution of the display apparatus when displayed.
Recently, three-dimensional (3D) video contents are becoming more and more popular. However, the storage/transmission of the 3D video content may be different from that of the 2D video content. Thus, the conventional letterbox detection applicable to letterboxed frames of a 2D video input may not be suitable for letterboxed frames of a 3D video input, and performing the conventional letterbox detection upon the 3D video input may fail to correctly detect and remove the letterbox margins presented in each video frame of the 3D video input.